I've used the Gmail cookbook as a base for this one.
So if we change it we may should change it in the whole docs, otherwise it would for example  read like
* How to use Gmail to send Emails
* How to use the Cloud to Send E-Mails
in the TOC.

Btw, I've found a lot of such words that are spelled differently across the docs; I'll create an issue listing them, we could vote for the correct one and then I'll update the docs.